Functional brain imaging has tremendous applications. The existing methods for functional brain imaging include functional Magnetic Resonant Imaging (fMRI), scalp electroencephalography (EEG), implanted EEG, magnetoencephalography (MEG) and Positron Emission Tomography (PET), which have been widely and successfully applied to various brain imaging studies. To develop a new method for functional brain imaging, here we show that the dielectric at a brain functional site has a dynamic nature, varying with local neuronal activation as the permittivity of the dielectric varies with the ion concentration of the extracellular fluid surrounding neurons in activation. Therefore, the neuronal activation can be sensed by a radiofrequency (RF) electromagnetic (EM) wave propagating through the site as the phase change of the EM wave varies with the permittivity. Such a dynamic nature of the dielectric at a brain functional site provides the basis for an RF EM wave approach to detecting and imaging neuronal activation at brain functional sites, leading to an RF EM wave approach to functional brain imaging.

The food preferences of paddlefish (Polyodon spathula) in polyculture with bighead carp (Aristichthys nobilis) are unknown. Three consecutive analyses of gastrointestinal contents of paddlefish and bighead carp were conducted at 3d, 11d and 19d after introduction into the non-fed ponds. The objectives of this study were to test for competitive interactions between bighead carp and paddlefish, and to document their preferred prey when the two species have a limited food resource. The results showed that paddlefish and bighead carp are basically competitive in their diets. When they were cultured in one pond at the same density, paddlefish fed more quickly and efficiently, depleting the food resources for bighead carp; however, bighead carp were able to switch and trap small food items with the decrease in available food resources. Moreover, larger zooplankton abundance declined in ponds after fish were introduced.